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<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE cref SYSTEM "cref.dtd">
<cref>
<header>
<copyright>
<year>1996</year><year>2013</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
The contents of this file are subject to the Erlang Public License,
Version 1.1, (the "License"); you may not use this file except in
compliance with the License. You should have received a copy of the
Erlang Public License along with this software. If not, it can be
retrieved online at http://www.erlang.org/.
Software distributed under the License is distributed on an "AS IS"
basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
the License for the specific language governing rights and limitations
under the License.
</legalnotice>
<title>erl_malloc</title>
<prepared>Torbjörn Törnkvist</prepared>
<responsible>Torbjörn Törnkvist</responsible>
<docno></docno>
<approved>Bjarne Däcker</approved>
<checked>Torbjörn Törnkvist</checked>
<date>980703</date>
<rev>A</rev>
<file>erl_malloc.sgml</file>
</header>
<lib>erl_malloc</lib>
<libsummary>Memory Allocation Functions</libsummary>
<description>
<p>This module provides functions for allocating and deallocating
memory.</p>
</description>
<funcs>
<func>
<name><ret>ETERM *</ret><nametext>erl_alloc_eterm(etype)</nametext></name>
<fsummary>Allocates an ETERM structure</fsummary>
<type>
<v>unsigned char etype;</v>
</type>
<desc>
<p>This function allocates an <c><![CDATA[(ETERM)]]></c> structure.
Specify <c><![CDATA[etype]]></c> as one of the following constants:</p>
<list type="bulleted">
<item>
<p>ERL_INTEGER</p>
</item>
<item>
<p>ERL_U_INTEGER <c><![CDATA[/* unsigned integer */]]></c></p>
</item>
<item>
<p>ERL_ATOM</p>
</item>
<item>
<p>ERL_PID <c><![CDATA[/* Erlang process identifier */]]></c></p>
</item>
<item>
<p>ERL_PORT</p>
</item>
<item>
<p>ERL_REF <c><![CDATA[/* Erlang reference */]]></c></p>
</item>
<item>
<p>ERL_LIST</p>
</item>
<item>
<p>ERL_EMPTY_LIST</p>
</item>
<item>
<p>ERL_TUPLE</p>
</item>
<item>
<p>ERL_BINARY</p>
</item>
<item>
<p>ERL_FLOAT</p>
</item>
<item>
<p>ERL_VARIABLE</p>
</item>
<item>
<p>ERL_SMALL_BIG <c><![CDATA[/* bignum */]]></c></p>
</item>
<item>
<p>ERL_U_SMALL_BIG <c><![CDATA[/* bignum */]]></c></p>
</item>
</list>
<p><c><![CDATA[ERL_SMALL_BIG]]></c> and <c><![CDATA[ERL_U_SMALL_BIG]]></c> are for
creating Erlang <c><![CDATA[bignums]]></c>, which can contain integers of
arbitrary size. The size of an integer in Erlang is machine
dependent, but in general any integer larger than 2^28
requires a bignum.</p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_eterm_release(void)</nametext></name>
<fsummary>Clears the ETERM freelist</fsummary>
<desc>
<p>Clears the
freelist, where blocks are placed when they are
released by <c><![CDATA[erl_free_term()]]></c> and
<c><![CDATA[erl_free_compound()]]></c>. </p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_eterm_statistics(allocated, freed)</nametext></name>
<fsummary>Reports term allocation statistics</fsummary>
<type>
<v>long *allocated;</v>
<v>long *freed;</v>
</type>
<desc>
<p><c><![CDATA[allocated]]></c> and <c><![CDATA[freed]]></c> are initialized to
contain information about the fix-allocator used to allocate
ETERM components. <c><![CDATA[allocated]]></c> is the number of blocks
currently allocated to ETERM objects. <c><![CDATA[freed]]></c> is the
length of the freelist, where blocks are placed when they are
released by <c><![CDATA[erl_free_term()]]></c> and
<c><![CDATA[erl_free_compound()]]></c>. </p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_free_array(array, size)</nametext></name>
<fsummary>Frees an array of ETERM structures</fsummary>
<type>
<v>ETERM **array;</v>
<v>int size;</v>
</type>
<desc>
<p>This function frees an array of Erlang terms.</p>
<p><c><![CDATA[array]]></c> is an array of ETERM* objects.
</p>
<p><c><![CDATA[size]]></c> is the number of terms in the array.</p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_free_term(t)</nametext></name>
<fsummary>Frees an ETERM structure</fsummary>
<type>
<v>ETERM *t;</v>
</type>
<desc>
<p>Use this function to free an Erlang term.</p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_free_compound(t)</nametext></name>
<fsummary>Frees an array of ETERM structures</fsummary>
<type>
<v>ETERM *t;</v>
</type>
<desc>
<p>Normally it is the programmer's responsibility to free each
Erlang term that has been returned from any of the
<c><![CDATA[erl_interface]]></c> functions. However since many of the
functions that build new Erlang terms in fact share objects
with other existing terms, it may be difficult for the
programmer to maintain pointers to all such terms in order to
free them individually.
</p>
<p><c><![CDATA[erl_free_compound()]]></c> will recursively free all of the
sub-terms associated with a given Erlang term, regardless of
whether we are still holding pointers to the sub-terms.
</p>
<p>There is an example in the User Manual under "Building
Terms and Patterns"
</p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_malloc(size)</nametext></name>
<fsummary>Allocates some memory</fsummary>
<type>
<v>long size;</v>
</type>
<desc>
<p>This function calls the standard
<c><![CDATA[malloc()]]></c> function. </p>
</desc>
</func>
<func>
<name><ret>void</ret><nametext>erl_free(ptr)</nametext></name>
<fsummary>Frees some memory</fsummary>
<type>
<v>void *ptr;</v>
</type>
<desc>
<p>This function calls the standard
<c><![CDATA[free()]]></c> function. </p>
</desc>
</func>
</funcs>
</cref>
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